Generalized Multi-Protocol Label Switching (GMPLS) signaling extensions, described in Request for Comments (RFC) 3473, entitled Generalized Multi-Protocol Label Switching (GMPLS) Signaling Resource ReserVation Protocol-Traffic Engineering (RSVP-TE) Extensions published January 2003, may be used to set up and signal co-routed bidirectional packet traffic engineering (TE) tunnels. An example of a bidirectional packet TE tunnel is two Multi-Protocol Label Switching (MPLS) TE label switched paths (LSPs), where one of the MPLS TE LSPs is a forward direction LSP (e.g., extending from a head-end node of the TE tunnel to a tail-end node of the tunnel) and the other of the MPLS TE LSPs is a reverse direction LSP (e.g., extending from the tail-end node to the head-end node). Alternatively, an associated Resource Reservation Protocol (RSVP) signaling method, described in Zhang et al., RSVP-TE Extensions for Associated Bidirectional LSPs <draft-ietf-ccamp-mpls-tp-rsvpte-ext-associated-lsp-03> Internet Draft, March 2012, can be used to set up and signal co-routed or non co-routed bidirectional packet TE tunnels. As used herein, a co-routed bidirectional packet TE tunnel denotes a bidirectional tunnel where the forward direction LSP and reverse direction LSP utilize the same path, e.g., the same node(s) and link(s). In contrast, a non co-routed bidirectional packet TE tunnel denotes a bidirectional tunnel that utilizes two different paths, i.e., the forward direction LSP path is different than the reverse direction LSP path.
It may be beneficial for the head-end node to indicate, e.g., to one or more nodes of the bidirectional packet TE tunnel, the provisioning of the LSPs to ensure appropriate signaling, handling and control of, e.g., the reverse direction LSP. As used herein, provisioning denotes, e.g., the configuration of the LSPs as co-routed or non co-routed; that is, whether the LSPs of the bidirectional TE tunnel are co-routed or non co-routed. Although a system administrator may construct a set of rules for the node(s) to determine whether the LSPs are co-routed (or not) using RSVP signaling messages and objects, such construction may lead to ambiguity and interoperability issues as different administrators may construct different rules to infer whether the LSPs are co-routed (or not).